<p>With climate change and population aging, it has become important to motivate older adults to engage in pro-environmental behaviors. Compared with younger adults, older adults may have lower ecological risk perceptions (perceived personal harm and worry) and higher social generativity (concern for future generations). The former may make them less likely, while the latter may make them more likely, to engage in pro-environmental behaviors. This study examined age-related pro-environmental behaviors when these two factors worked together. A survey was conducted among 235 older (Mage = 70.64, age range 64–93) and 238 younger adults (Mage = 25.91, age range 19–37) in Hong Kong, a subtropical city facing increasing temperatures. Despite no significant age differences in ecological risk perceptions, older adults reported greater recycling, political support, consumption-related pro-environmental behaviors, and higher social generativity compared to younger adults. Younger adults exhibited the same level of pro-environmental behaviors as older adults did at higher levels of social generativity. When asked why they engaged in pro-environmental behaviors, older adults reported more pro-environmental, habitual, and norm-conforming reasons, while younger adults reported more monetary reasons. These findings suggest that although older adults do not perceive higher ecological risks, they may engage in more pro-environmental actions for the sake of future generations. Implications for future studies and practices were discussed.</p>